Prime Minister Julia Gillard has strongly condemned the rioters who took part in a violent protest over an anti-Islamist video as ''extremists''.

''What we saw in Sydney on the weekend wasn't multiculturalism but extremism,'' she said last night in a speech to the Australian Multicultural Council.

Saturday's protest in Sydney, one of many worldwide, was sparked by the film Innocence of Muslims, which was produced in the United States and portrays the prophet Muhammad as a fraud, womaniser, homosexual and madman.

Ms Gillard previously described the film as repulsive and condemned the violence.

Opposition Leader Tony Abbott has called for the visa of British Muslim leader Taji Mustafa to be revoked to prevent him speaking at the Hizb ut-Tahrir's annual conference at Bankstown in Sydney.

Mr Abbott said this week the group had regularly been on the record calling for the destruction of Israel and some of its leaders had called for violence against Australian troops in Afghanistan.

However, Parliament was told the organisation was not a proscribed terrorist organisation.

Ms Gillard said last night multiculturalism was not just the ability to maintain diverse backgrounds and cultures.

''It is the meeting place of rights and responsibilities where the right to maintain one's customs, language and religion is balanced by an equal responsibility to learn English, find work, respect our culture and heritage, and accept women as full equals,'' she said.

''Where there is non-negotiable respect for our foundational values of democracy and the rule of law, and any differences we hold are expressed peacefully.

''Where old hatreds are left behind, and we find shared identity on the common ground of mateship and the Aussie spirit of a fair go.

''True multiculturalism'' had a very different face [to the riots], the Prime Minister said.

It was the face of ''a new migrant studying hard in an English language class, working two jobs to put their kids through school or lining up to vote for the very first time. ''True multiculturalism includes, not divides, it adds more than it takes. In the end, multiculturalism amounts to a civic virtue since it provides us with a way to share the public space, a common ground of inclusion and belonging for all who are willing to 'toil with hearts and hands'.''

''And because it always summons us toward a better future, multiculturalism is an expression of progressive patriotism in which all Australians, old and new, can find meaning.''

Also addressing the council, migrant businessman Frank Lowy said the response to the protests in Sydney proved Australia's multicultural society was both strong and mature.